How to Make a Cabbage pH Indicator

Transcript: How to Make a Cabbage pH Indicator

Hi, I'm Dr. Anne Helmenstine for About.com. I'm going to show you how to make your own pH indicator and pH paper from kitchen materials, which you can use to test the acidity of common household chemicals.

Cabbage pH Indicator Materials

All you need for this project are a couple of leaves from a red or purple cabbage and a coffee filter.

Prepare the pH Indicator Solution

Tear the cabbage leaves into small pieces and set them on a microwave-safe plate. Microwave the cabbage for a few minutes, until the leaves are soft and cooked. Allow the cabbage to cool, then press the coffee filter into the leaves to absorb the colored cabbage juice. When the coffee filter has been completely saturated with juice, set it to

the side and allow it to dry.

Test Chemicals with Homemade pH Paper

The colored coffee filter is your pH paper, but it will be easier to work with if you cut it into several small pH paper test strips.

Drip the chemical you wish to test onto one of these strips. The color change of the pH paper indicates the pH or acidity of the chemical. To be an acid or a base, a chemical needs to contain some water. Certain chemicals, such as vegetable oil, do not contain water and will not change the color of your pH test strip. Can you predict which chemicals are acids or bases?

I hope you've enjoyed this easy pH chemistry project. To get ideas for more projects, visit me on the web at About.com. Thanks for watching!